//Convert a string to spinal case. Spinal case is all-lowercase-words-joined-by-dashes.
function spinalCase( str ) {
  let regex = str.replace( /([a-z])([A-Z])/g, "$1 $2" )
  return regex.replace( /\s+|_+/g, "-" ).toLowerCase()
}
console.log( spinalCase( "The_Andy_Griffith_Show" ) )
console.log( spinalCase( "thisIsSpinalTap" ) )
console.log( spinalCase( "AllThe-small Things" ) )

//1st replace puts a space before any encountered uppercase characters in the string.$1 is the first group from your regular expression, $2 is the second, puts space between $1=>lowercase ie[a-z] and 2nd $2=>uppecase [A-Z]
//2nd replaces spaces and underscores with dashes and change to lowercase
